In video display devices such as television receivers, it is known that a synchronization signal, which is used for displaying a video on a display, is used as an operation reference signal used for performing video processing. However, there are cases where the synchronization signal is disturbed due to switching between video input sources (for example, switching between an input from a recording medium reproducing device and an input from a TV tuner), switching between resolutions, switching between video modes (switching between the NTSC mode and the PAL mode), or the like. When such a disturbance of the synchronization signal occurs, the video processing is not appropriately performed, whereby the display on the display device is disturbed as well.
In addition, while there are video display devices in which control data used for controlling video processing in a video processing unit is acquired from a microcomputer and is used for the video processing, in such a case, communication is performed between a video processing IC and the microcomputer by generating a communication timing signal using a video synchronization signal, and accordingly, there is a problem in that the communication with the microcomputer becomes unstable as the synchronization signal is disturbed. Regarding this problem, video processing devices are proposed which are capable of performing communication for reliably controlling video processing by detecting no-input of a video signal and generating the communication timing signal in a self-operative manner even in a case where a video signal is not input (for example, see Patent Literature 1).